JPS63312977A - Film forming device - Google Patents

Abstract

PURPOSE:To effectively utilize all the high-density plasma produced by a microwave power for forming a film by supplying a microwave power to a coaxial pipe opened to the inside of a vacuum vessel, and arranging a target on the end of an inner conductor of the coaxial pipe. CONSTITUTION:The coaxial pipe 7 is opened to the inside of the vacuum vessel 1, the target 4 is arranged on the end of the inner conductor 3, the outer conductor 2 is connected to a microwave oscillator 5 through a waveguide 6, and a magnet 18 is arranged on the outer periphery of the end. In addition, the length of the outer conductor 2 is made larger than that of the inner conductor 3. A negative voltage is impressed on the target 4 from an electric power source 17 through the inner conductor 3, and the grounded outer conductor 2 is used as a positive counter electrode. Under such conditions, a gas supplied from a supply source 11 is formed into plasma 16 in the vicinity of the target 4, hence the target 4 is efficiently sputtered, and a film is formed on a substrate 15 opposed to the plasma 16.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a film forming apparatus by sputtering using microwave plasma.

Conventional technology Conventional sputtering equipment uses direct current discharge or 13.56 M as a means of turning inert gas such as argon into plasma.
A high frequency discharge of Hz is used.

However, simply generating plasma by direct current discharge or high frequency discharge results in a slow film formation rate due to the low density of the plasma. Therefore, a magnetron sputtering apparatus is generally used in which a magnet is placed near the target to increase the plasma density and improve the film formation rate.

Regarding electric power, in recent years, a sputtering apparatus using microwave discharge has been proposed to increase plasma density, as seen in, for example, Japanese Patent Application Laid-Open No. 61-272372.

Problems to be Solved by the Invention However, in the conventional example described above, the plasma generation chamber and the target are located far apart, so that the high-density plasma generated in the plasma chamber is transported to the surface of the target to some extent. There was a problem in that the plasma that was generated at high density could not be fully utilized.

Therefore, an object of the present invention is to provide a film forming apparatus that can effectively utilize almost all of the generated high-density plasma.

Means for Solving the Problems The present invention comprises a coaxial tube opening into a vacuum container, a target disposed at an end of an inner conductor of the coaxial tube, and means for supplying microwave power to the coaxial tube. This is a film-forming device that does this.

Working plasma can be generated very close to the target, preventing the plasma from dispersing to the surroundings, and making full use of the high-density plasma generated by microwave discharge.

Example A schematic configuration diagram of an embodiment of the present invention is shown in FIG.

In Fig. 1, 1 is a vacuum vessel, 2 is an outer conductor of a coaxial tube opened in the vacuum vessel 1, and 3 is an inner conductor of the same coaxial tube, with a target 4 placed at the end, which is connected to the surroundings of the plasma. In order to prevent this from spreading, the length of the outer conductor 2 inside the vacuum vessel 1 is configured to be longer than the length of the inner conductor 3. Reference numeral 5 denotes a microwave power oscillator, and the microwave oscillated from the oscillator 5 is supplied to a coaxial tube section 7 through a square wave tube 6. Here, the taper portion 8 is an element for supplying high-power microwaves from the square wave tube 6 to the coaxial tube 7 without loss, and is also for widening the coaxial tube 9f''i.

10 is a dielectric material such as alumina, which seals the vacuum. An inert gas such as argon is supplied through a gas supply pipe 11 and exhausted through an exhaust port. The microwaves are matched by two movable short circuit plates 12 and 13, and a water cooling tube 14 is inserted into the inner conductor 3 to cool the target 4 and the inner conductor 3 of the coaxial tube. The substrate 16 is placed facing the target 4, and a thin film is formed on the substrate 15 by causing inert gas ions in the plasma 16 generated by microwave discharge to collide with the target 4 using a power source 17. In this embodiment, the outer conductor 2 of a grounded coaxial tube is used as a target electrode at a positive potential with respect to the target 4 which is at a negative potential due to the power source 17.

Further, 18 is a magnet for compressing the plasma 16 into the center of the coaxial tube, that is, the surface of the target 40 at high density.

With this configuration, high-density plasma can be generated at the end of the coaxial tube opened into the vacuum container, that is, near the target 4.

Note that although a coaxial tube in which the outer conductor 2 and inner conductor 3 have circular cross sections is usually used, these are not limited to circular shapes and may be rectangular.

Further, although only 18 magnets were used in this embodiment, magnets 19 may be arranged as shown in FIG. 2, which is an enlarged cross-sectional view of a portion of the target 4, so as to be used in a magnetron sputtering apparatus. Additionally, the magnets 18 of FIG. 1 may be configured to generate a cupped field, or the magnets may be arranged in other effective manners.

Effects of the Invention According to the present invention, high-density plasma can be generated in the vicinity of the target using microwave energy without being dispersed to the surroundings, so that almost all of the generated plasma can be effectively used for sputtering.

As a result, the film formation rate can be further increased.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a film forming apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram of a different embodiment of the present invention. 2...Outer conductor of coaxial tube, 3...Inner conductor of coaxial tube, 4...Target, 6...
Microwave oscillator. Name of agent: Patent attorney Toshio Nakao and one other person
X Empty container a - outer conductor of coaxial tube 3 - inner conductor of coaxial tube Fig. 2

Claims (3)

[Claims] (1) A film forming apparatus comprising a coaxial tube opened into a vacuum container, a target disposed at an end of an inner conductor of the coaxial tube, and means for supplying microwave power to the coaxial tube. (2) The film forming apparatus according to claim 1, wherein the length of the outer conductor of the coaxial tube in the vacuum container is longer than the length of the inner conductor. (3) The inner conductor of the coaxial pipe and the target are brought into electrical contact, a negative voltage is applied to the inner conductor, and the outer conductor of the coaxial pipe is made to have a positive potential with respect to the inner conductor. A film forming apparatus according to scope 1 or 2.